On Monday night, Commerce Secretary Wilbur Ross announced that he is directing the Census Bureau to ask all respondents to the 2020 census to report their citizenship status. He made the decision over the strong objections of former census directors representing both Republican and Democratic administrations, 60 members of Congress, 161 Republican and Democratic mayors, 19 state attorneys general, more than 170 civil rights organizations, and prominent business leaders, among others, all of whom strongly advised against adding a citizenship question. The move raises serious concerns that the upcoming census will be a major failure, harming our democracy, communities and businesses and painting an inaccurate picture of America’s population.

Here’s what you should know about what’s at stake:

Why is it a problem for the census to ask about each individual’s citizenship status?

The U.S. Constitution requires the census, every 10 years, to count each and every individual in the country, regardless of age, race, gender, ethnicity or citizenship status.

Census professionals agree that a citizenship question will significantly reduce census participation, both by citizens and non-citizens. As former Census Bureau directors recently explained to the U.S. Supreme Court, adding the citizenship question will create a chilling effect on participation by raising privacy concerns and stoking the fears of undocumented individuals that their responses may be used against them. Census professionals currently employed at the bureau have already reported that a heightened environment of suspicion and fear is complicating their work in the field preparing for the census, even before a citizenship question has been added to their questionnaires. Under these circumstances, if the citizenship question remains, the resulting population counts that we all rely on will be wrong.

Under the Constitution, seats in the House of Representatives are divided among the states every 10 years based on the population count that the census generates. Seats in the Electoral College are allocated the same way. States also use census data to draw district lines for congressional and state legislative seats – a necessary process to make sure communities are fairly represented. Census data also guides the distribution of hundreds of billions of dollars in federal aid. It informs statistical publications that help business owners and local governments make key decisions on matters ranging from marketing and investment to the assignment of police beats. And it provides academic researchers, journalists, and others with invaluable demographic information.

What should you make of Secretary Ross’ claim that the citizenship question will have little impact?

Ross is an outlier in his belief that a citizenship question will not have a big impact on census participation. In explaining his decision, he acknowledged that the Census Bureau itself and other key stakeholders objected to the addition of a citizenship question because they believed it would depress participation in the census. Their belief was based on several empirical analyses, as well as on decades of experience by professionals administering and supporting the census.

Nonetheless, Ross did not heed their advice, claiming that there is “no definitive empirical support” for their belief ― an unusually high standard. The basis for Ross’ claim that the citizenship question will not impact participation after all? A conversation he had with a television polling firm executive. Needless to say, there is very little in common between the census ― the largest government data-collection operation ― and a short television consumer survey.

Despite claims to the contrary in a letter from Department of Justice officials, information on the citizenship status of every person living in the country simply isn’t necessary to enforce our civil rights laws. For decades — and under both Democratic and Republican administrations — the Department of Justice has pursued its civil rights mission without resorting to this kind of information. The only civil rights law for which citizenship data is at all useful is the portion of the federal Voting Rights Act prohibiting discrimination in the drawing of district lines. Yet, no citizenship question has appeared on the census form sent to every household since the passage of the Voting Rights Act in 1965. Regular yearly surveys of a sample of households already provide current and adequate data for civil rights enforcement to government, litigators and the courts.

Rather than improving upon the data relating to non-citizens, civil rights litigators generally believe that adding a citizenship question will lead to less accurate data about the number of non-citizens and citizens alike.

While we can’t see into the minds of the people who pushed for the citizenship question, unsavory political motives might be in play.

Changing apportionment of congressional seats. The most likely impact of the citizenship question is to depress census participation — and thus, headcount— especially among immigrants, members of mixed-status households and communities of color. States with high concentrations of those populations are likely to experience dramatic “undercounts” of their residents. If the undercounts are significant, then those states could lose congressional seats, which are apportioned based on the census counts. In other words, the citizenship question might be a ploy to change the distribution of seats in Congress.

Meddling with redistricting. It might also be an attempt to meddle in the next round of redistricting, which is set to begin in 2021. Every state currently uses the census’s total population figures to draw district lines. For years, a group of conservative political activists have called for states to base their district lines not on their total population, but instead on their population of citizens who are voting age. The impact of such a change would be dramatic, altering every state legislative map in the country. It would especially harm communities with high immigrant populations, as well as those with high youth populations. In 2015, the Supreme Court rejected an attempt to require states to base redistricting decisions on citizen voting-age population figures. It did not, however, address the question of whether it is permissible for states who wish to use such figures for redistricting to do so. By requiring the census to track citizenship status, the administration might be laying the groundwork to push for redistricting based on citizenship figures.

According to news reports, the political appointee who requested the change, John Gore, previously defended Republican redistricting plans that were later found to be discriminatory, and another appointee to the census, Christopher Stanley, previously worked for a member of Congress who repeatedly introduced legislation to add a citizenship question to the census.

Can the federal government use information collected from the census to pursue immigration actions?

No. The law is crystal clear: The Census Bureau cannot share personal information with other agencies, that information cannot be used for any purpose other than statistical ones, and it cannot be used to harm the people who provide that information.

Congress has long understood that the privacy and confidentiality of the information that census participants provide to the government is absolutely essential to ensuring everyone participates confidently and fully in the census. So, in the Census Act, Congress included the strongest privacy and confidentiality protections that exist in federal law. Employees of the Census Bureau are prohibited from sharing the personal information that they collect with anyone outside the bureau, even with the employees of other federal agencies. And even when personal information stays inside the Census Bureau, the Bureau’s employees can only use it to create statistical products that contain no information that can be traced back to an individual personally. There are severe criminal penalties to back these rules up, including a fine of up to $5,000 or five years of jail time for violating the Census Act.

Even in the face of these protections, some people will be reluctant to participate in the census, either because they are unfamiliar with their rights and what the census is all about, or because they do not trust the government to follow the law, especially under an administration that regularly makes headlines with anti-immigrant words and actions. Public education about these rights, and strong reassurances by the administration that it will abide by its legal obligations, will be necessary to counteract this pressure.

Can anything be done to block the citizenship question, or is this a done deal?

There’s plenty that can be done between now and Census Day on April 1, 2020, to keep the citizenship question off the census. The Commerce Department itself can modify its position, using the powers it has under the Census Act. Congress can pass legislation to override the Commerce Department’s decision, using its basic authority under the Constitution. And ordinary citizens can advocate before both of those bodies.

Even if we reach Census Day with a citizenship question on the form, the administration will need to work to alleviate concerns that people’s responses will be used against them. Among other things, the administration should publicly commit to uphold the Census Act’s basic privacy and confidentiality protections, instruct federal agencies — including the Department of Homeland Security — to pledge not to request or use census data for their own operations and to suspend immigration enforcement actions during census time to ensure that people can answer their doors to census takers without fear.